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Dissolved oxygen and the temperature of waterScience project video


While most of us do not give much thought to water quality, serious aquarists are keenly aware of the importance of maintaining water quality. But while aquarists are careful to maintain ph, nitrates, and ammonia levels, many do not give the same attention to the level of dissolved oxygen (DO). An understanding of the relationship between temperature and DO is the subject of this science project. With the understanding gained from this experiment, you will have insight on how tropical and cold water fish are able to survive in their respective environments.


Determine the relationship between temperature of water, and dissolved oxygen.

Scientific Terms

Dissolved oxygen


Sub-atomic particles are more active at higher temperatures, resulting in oxygen atoms breaking their molecular bonds. Water is composed of one hydrogen atom and two oxygen atoms. Once the atomic bond is broken, the oxygen atoms break free, resulting in there being less oxygen in the water. At cooler temperatures, there is less activity at the atomic level; hence, oxygen is retained in the water. At the other extreme, all oxygen is lost when water is boiled. Some warm water fish species have adapted to lower levels of oxygen in water, by obtaining additional oxygen from the atmosphere.

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    Does not include time required to obtain a water quality kit, which may be purchased online or at an aquarium shop.
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    This science fair project involves an electric aquarium heater and water as well as chemicals contained in the water quality kit. Appropriate care should be taken to avoid injuries.